The comments from Cork East deputy Tom Barry come amid already heightened tensions between the coalition partners over the changes to means tests for college grants.

Mr Barry also said Labour thinks farmers buy "tractors to go to Mass in – not that any of them would know the inside of a church anyway".

Mr Quinn is willing to compromise on the means test, amid signs he will focus on "non-productive" assets – such as second homes and savings – and exclude "productive" assets worth less than €750,000 which generate income.

But the issue has driven a clear wedge between the two parties. Mr Quinn's stance has been backed up by prominent Dublin North-Central Labour TD Aodhan O Riordain.

But Mr Barry said some Labour people had "no clue" about farming. He said Labour had now taken a "tit-for-tat" attitude to Government, trying to get its own victories for perceived Fine Gael gains, like the public sector pay deal. "Either they grow up or they can go their own way," Mr Barry said.

Fine Gael Waterford TD John Deasy said Mr Quinn's revised proposals will be watched very carefully, even if they do exclude income producing assets.

The issue erupted again last week when Agriculture Minister Simon Coveney briefed Fine Gael's internal agriculture committee on the issue.

He said he and Taoiseach Enda Kenny were opposed to Mr Quinn's original proposals, and told deputies and senators his and the Taoiseach's staff outlined their opposition to Mr Quinn's officials.

Sources at the meeting – attended by around 20 TDs – said Mr Coveney made it clear the original proposals would not be accepted.

Sources also said Mr Coveney said he may have been defeated on a vote at Cabinet, but insisted the proposals would not have made it that far anyway. Mr Coveney has since denied he said this, and claimed what he did say was "that no proposals had come to government".